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water pump jockey wheel or top timing chain guide maybe,,would pull the aux belt off and run it see if noise goes away,, if dont then timing chain related,, oil pump has a slight whrrrr to it as well normal with some miles on board
 

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Discussion Starter · #22 ·
Hi guys,

since march the Mini hadn't had a issue so far, but today the engine light came back on AGAIN!
(Timing Chain was changed, oil was changed, a new sensor came in and so far)

And oh wonder, the error code P0030 says oxygen sensor :cautious: how can that be?

Does anyone have a clue?

Could it be that the valve stem seals are not the best anymore, therefore the engine uses a litte oil and that is damaging the sensor again?
 

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Hi guys,

since march the Mini hadn't had a issue so far, but today the engine light came back on AGAIN!
(Timing Chain was changed, oil was changed, a new sensor came in and so far)

And oh wonder, the error code P0030 says oxygen sensor :cautious: how can that be?

Does anyone have a clue?

Could it be that the valve stem seals are not the best anymore, therefore the engine uses a litte oil and that is damaging the sensor again?
totally your prob right link below for the last 2 mini's that had these issues as they all do with age and 100k ish
also when rebuilding them must do the cat and 02 sensors as well as will end up badly if dont,
 

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Discussion Starter · #24 ·
totally your prob right link below for the last 2 mini's that had these issues as they all do with age and 100k ish
also when rebuilding them must do the cat and 02 sensors as well as will end up badly if dont,
Hi Mike,

first of all sorry, my english isnt the best in these technical things, as far as I understand the bad valve stem seals are damaging the O2 sensor again. (The car is useing a little oil and the shop said, the oil consumption is caused by the hardened valve stem seals and by the repair due to the higher intake manifold
Increased negative pressure.)

Am I right with this?
 

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Hi Mike,

first of all sorry, my english isnt the best in these technical things, as far as I understand the bad valve stem seals are damaging the O2 sensor again. (The car is useing a little oil and the shop said, the oil consumption is caused by the hardened valve stem seals and by the repair due to the higher intake manifold
Increased negative pressure.)

Am I right with this?
yes totally i have repaired a lot of these engines like it ,, and to be honest its pays to pull the pistons at same time as have head off and use better piston rings as factory use single piece rings for oil rings and are crap to be honest, i use 3 piece sets worn really well also must hone the bores as well,

on that page link i gave you you can see how the valves and stem seals go they all do it around 10 year old as rubber and age dont work well then add dirty oil and heat etc ,
 

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Discussion Starter · #26 ·
yes totally i have repaired a lot of these engines like it ,, and to be honest its pays to pull the pistons at same time as have head off and use better piston rings as factory use single piece rings for oil rings and are crap to be honest, i use 3 piece sets worn really well also must hone the bores as well,

on that page link i gave you you can see how the valves and stem seals go they all do it around 10 year old as rubber and age dont work well then add dirty oil and heat etc ,

Hi Mike, I need your help again...

I changed the valve stem seals and put a new O2 sensor in and today around 4000km later the engine light comes on AGAIN, at this point the timing chain and the valve stem seals were changed, what on earth could damage this thing again?! Maybe the catalytic converter is damaged as well?
 

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the 02 sensors react to the gases post and pre cat if cat blocked will over heat upstream and will also cause low reading from down stream, it will also have effect on upstream sensor reaching 600c ie the switching point to closed loop running
 

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Discussion Starter · #28 ·
the 02 sensors react to the gases post and pre cat if cat blocked will over heat upstream and will also cause low reading from down stream, it will also have effect on upstream sensor reaching 600c ie the switching point to closed loop running
thanks a lot for your answer, is there a way to test if the cat is broken or damaged?

edit:

and could a worn timing chain and bad stem valves had negative effects to the cat?
 

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yes to all timing chain biggest effect car runs lean or rich due to retard running and more throttle to get it to revs causes more damage,
vale stem seals the rubber goes hard 8 years ish or 100k ish max, the oil seeps to cat and goes hard carbon blocks the cat,, when this happens causes back pressure and heat and finishes off things like piston rings and loads the oil with carbon more so,, hence why a engine refresh around 80k is best option with these engines and must change the cat and sensors at same time as will be all done at those mileages,,, to limit this outcome 60k chain changes a must and oil changes around 8-10k a must,, 20k oil changes its silly destroys them, also the latest spec thermostat housing a must do job at same time, older ones were 112c the new spec is 104c genuine parts only best or febi do a ok one bit cheaper .
 

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Discussion Starter · #30 ·
yes to all timing chain biggest effect car runs lean or rich due to retard running and more throttle to get it to revs causes more damage,
vale stem seals the rubber goes hard 8 years ish or 100k ish max, the oil seeps to cat and goes hard carbon blocks the cat,, when this happens causes back pressure and heat and finishes off things like piston rings and loads the oil with carbon more so,, hence why a engine refresh around 80k is best option with these engines and must change the cat and sensors at same time as will be all done at those mileages,,, to limit this outcome 60k chain changes a must and oil changes around 8-10k a must,, 20k oil changes its silly destroys them, also the latest spec thermostat housing a must do job at same time, older ones were 112c the new spec is 104c genuine parts only best or febi do a ok one bit cheaper .
Ok I thought about this as well, now the car has arround 141k the timing chain was changed at arround 120k and the valve stem seals at around 136k
So the engine was driven quite long with these issues, that could have damage the cat
 

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Discussion Starter · #31 ·
yes to all timing chain biggest effect car runs lean or rich due to retard running and more throttle to get it to revs causes more damage,
vale stem seals the rubber goes hard 8 years ish or 100k ish max, the oil seeps to cat and goes hard carbon blocks the cat,, when this happens causes back pressure and heat and finishes off things like piston rings and loads the oil with carbon more so,, hence why a engine refresh around 80k is best option with these engines and must change the cat and sensors at same time as will be all done at those mileages,,, to limit this outcome 60k chain changes a must and oil changes around 8-10k a must,, 20k oil changes its silly destroys them, also the latest spec thermostat housing a must do job at same time, older ones were 112c the new spec is 104c genuine parts only best or febi do a ok one bit cheaper .
Mike do you know if I need a lifting platform to change the cat?
 
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